Medical Imaging: Less is More?
This past Monday (March 7, 2011), a 3D mammogram was performed in the United States for the first time and subsequent news stories have served to renew and escalate old controversies surrounding cancer screening. On the one hand, proponents argue that mammograms detect “between 80 and 90 percent of all breast cancers” (Ashton, 2011), allowing early treatment. Critics, however, point to several drawbacks: cost of the machines, radiation exposure, over diagnosis, false negatives and false positives. The 3D technique is expected have mixed results with respect to conventional mammography. Though it may reduce false positives and increase detection by 7%, it will nonetheless cost more, expose women to additional radiation and may not reduce the incidents of benign masses being discovered and treated as tumors (Salahi, 2010).
At this point, experts are saying that no detection strategy is perfect and it will take time to determine whether or not the new technique will save lives (Ashton, 2011; Salahi, 2010). In the meantime, the United States is a major consumer of diagnostic imaging equipment, having among the highest diffusion rates of mammographs, CT scanners, and MRI machines among OECD nations (OECD, 2010). It also spends more for health care on a per capita basis than any other OECD nation while ranking 25th in life expectancy (OECD, 2010). From this perspective, it is logical to ask whether technology – particularly unproven technology – is the key to good public health.
Source: OECD, 2010
Source: OECD, 2010
But non-3D mammography is not new; regular screening for women over 40 was first recommended by the American Medical Association in 1989 (Kevles, 1997). It seems that information accumulated over the past 22 years would give some insight into the efficacy of mammography. On this, the data are inconclusive. Howard, Richardson, and Thorpe (2009) found that the United States’ more aggressive screening program finds a higher breast cancer incidence rate, but results in a higher 5-year survival rate and a lower mortality rate than many European countries. However, they also state that the data do not necessarily indicate that more mammograms produce better outcomes.
Similar confusion can be found in OECD data. Although not an exact indicator of health, potential years of life lost (PYLL) may provide insight into the occurrence of premature, preventable death from a specific condition (OECD, 2010). If mammography were effective, one would expect higher screening rates to be correlated with lower PYLL values from breast malignancies, but this is not necessarily the case.
Source: OECD, 2010Given such questionable efficacy, one might ask how much cancer screenings are costing the public. At least one study concluded that even though the cost of diagnostic imaging equipment is growing, it has remained constant at 10% of hospital expenditures (Beinfeld & Gazelle, 2005). Hence medical imaging is not the only factor in rising spending. Ultimately, medical imaging costs are at the center of the struggle between health care providers’ best judgment, the medical device industry profit motive, medical insurance cost management, federal regulatory and investment policy, and the R&D that scientists and companies wish to pursue. This is a complex system to say the least.
If there is one possible path to a better system, it might be found by studying Japan. In 2004, Japan spent about half what the US did on health care per person; its population has a longer life expectancy, and its PYLL due to breast cancer is among the lowest in the OECD. It seems they are doing something right.
Source: OECD, 2010References
Ashton, J. (2011). 3D mammogram newest weapon against breast cancer. CBS Evening News. Retrieved from http://www.cbsnews.com/stories/2011/03/07/eveningnews/main20040349.shtml.>
Beinfeld, M. T., & Gazelle, G. S. (2005). Health Policy and Practice Radiology Diagnostic Imaging Costs: Are They Driving Up the Costs of Hospital Care? Radiology, 235(3), 934-939.
Howard, D. H., Richardson, L. C., & Thorpe, K. E. (2009). Cancer screening and age in the United States and Europe. Health Affairs, 28(6), 1838. Health Affairs. Retrieved March 11, 2011, from http://content.healthaffairs.org/cgi/content/abstract/28/6/1838.>
Kevles, B. H. (1997). Naked to the bone: Medical imaging in the twentieth century. Naked to the bone Medical Imaging in the Twentieth Century. New Brunswick, NJ: Addison-Wesley.
OECD. (2010). OECD Health Data. OECD Health Statistics. Retrieved from http://www.ecosante.org.ezproxy1.lib.asu.edu/index2.php?base=OCDE&langs=E...
Salahi, L. (2010). 3D Mammogram on the Brink of FDA Approval. ABC News. Retrieved from http://abcnews.go.com/Health/OnCallPlusBreastCancerNews/3d-imaging-detects-br...





